The goal of this research is to evaluate the role of infection in the pathogenesis of chronic bronchitis and emphysema. A study population of 120 patients with COPD and 30 normal control subjects were monitored over a seven-year period for episodes of acute respiratory illness and for changes in pulmonary function. Cultures for pathogenic bacteria, viruses, and mycoplasma were taken during and between periods of acute illness. Additional infections with these agents were diagnosed by serological methods. Clinical, physiologic and microbiologic data are now being correlated by computer and analyzed for evidence that specific infectious agents are related to the onset or progression of this disease. The influence of preventive and therapeutic factors on specific agents of pathogenic significance will be assessed. The role of smoking, air pollution, and genetic factors will also be assessed so that the role of infection can be placed in proper perspective. BIBLIOGRAPHIC REFERENCES: Smith, C.B., Golden, C.A., Kanner, R.E., and Renzetti, A.D., Jr.: Haemophilus influenzae and Haemophilus parainfluenzae in chronic obstructive pulmonary disease. Lancet 1:1253: 1255, 1976. Smith, C.B., Golden, C.A., Klauber, M.R., Kanner, R.E., and Renzetti, A.D., Jr.: Viral-bacterial interactions in patients with chronic bronchitis. J. Infect. Dis. 1976 (in press).